Abstract: A process uses a starting material including recycled post-consumer and industrial “scrap” thermoplastics based on polyester and polyamide, where a supply is obtained suitable for 3D printing/additive manufacturing/rapid prototyping with “Fused Deposition Model” (FDM), “Fused Filament Fabrication” (FFF) and similar technologies. The supply can have the form of a solid filament suitable to be used by “3D” printers, or it can form a pulverulent material to be used in more sophisticated printers, such as those with SLS technology. This method includes a series of first stages that consist of: a) Selecting the starting material which was originally produced by one of the processes of transformation; b) starting material is duly cleaned; c) once it is cleaned, the material is dried at temperatures greater than 100° C. but less than 240° C.; d) the material obtained thereof is driven into an extruder machine where it is subject to temperatures between 200° C. and 350° C.